Research On Modeling And Parametric Identification Of Rubber-bearings

Because of the complex nature of the excitation and the inherent non-linear dynamics characteristics of the base isolation system, the prediction of the dynamic response of rubber-bearings subject to strong earthquake is quite challenging. In order to describe the non-linear restoring force and to evaluate the possible damage of rubber-bearings during the normal operation or right after a major disaster, it is important to develop a suitable hysteretic model. Several hysteretic models for describing the dynamic behavior of rubber-bearings have been proposed in the literature, including piecewise-linear hysteretic models, polynomial hysteretic models, curvilinear hysteretic models, etc. In this paper, a simplified Wen model is proposed to describe the non-linear behavior of rubber-bearings, which has the advantages of being smooth-varying and physically motivated. Further, experimental tests using a particular type of rubber-bearing (GZN110) have been conducted to identify the parameters of the proposed hysteretic model. Based on experimental vibration data measured from sensors, a new system identification method, referred to as the sequential non-linear least-square estimation (SNLSE), has been used to identify the model parameters. The SNLSE approach has significant advantages over the extended Kalman filter (EKF) approach in terms of the stability and convergence of the solution as well as the computational efforts involved. Different excitation scenarios, including sinusoidal, white noise and several earthquakes, have been simulated and experimentally tested. The accuracy and effectiveness of the proposed approach have been demonstrated using experimental data. Experimental results demonstrate that the proposed simplified Wen model is capable of describing the non-linear behavior of rubber-bearings, and that the SNLSE approach is quite effective for identifying non-linear hysteretic parameter and for the prediction of displacement.